Many metal ions are essentially insoluble in aqueous systems having pH's ranging from approximately 6.0 to 9.0. Within this pH range, these metals, including but not limited to iron, zinc, aluminum and manganese, will deposit on heat transfer surfaces causing underdeposit attack. The addition of 2-hydroxyphosphonoacetic acid increases the solubility of these ions in solution, thereby reducing their tendency to deposit as insoluble salts and protecting against related corrosive attack.
U.S. Ser. No. 847,995 discloses a method for solubilizing aluminum ions in recirculating water systems using acrylic acid/sulfonic acid polymers.
2-hydroxyphosphonoacetic acid is commercially available from Ciba-Geigy under the tradename Belcor.RTM. 575. While 2-hydroxyphosphonoacetic acid is known in the water treatment art as a corrosion inhibitor and as a calcium carbonate scale inhibitor, the ability of 2-hydroxyphosphonoacetic acid and its salts to solubilize metal ions in aqueous systems is not known in the art.